A kind of PCB pad
Technical field
The utility model relates to a kind of PCB pad.
Background technology
Existing product often can be taken off the element in pcb board or burn-on in maintenance and debugging, but difficulty is larger while taking off as more elements of pin such as socket, connecting needle, transformers.As depicted in figs. 1 and 2, in figure, pad adopts circular pad 2, and in its Copper Foil 3, the thickness of copper sheet is 35 microns, and the thickness of place pcb board 1 is 1.6 millimeters, and the pin 6 of components and parts inserts in pad 2.Need first flatiron to be adjusted in higher temperature (400 degree left and right); Again flatiron repeatedly is placed on each component pin 6 repeatedly, in order to the scolding tin on component pin 6 is melted or removes; Finally, after scolding tin melts or removes, when element is loosening, element is pulled out.Because present most of electronic products is used unleaded tin welding mode, without the fusing point of slicker solder, be 280 degree, when this requires welding, external temperature will be in 350 to 450 degree left and right; To pull down element or load onto, flatiron must first melt tin, therefore the temperature of flatiron is very high, generally between 350 to 450 degree, and the time is longer, when bonding pad area less, at high temperature due to the effect of expanding with heat and contract with cold, add the pulling force while taking off element, so that the phenomenon that fraction is thin and pad Copper Foil that do not join with other cabling there will be copper sheet to warp or comes off is arranged in PCB, can cause the bad order of product, have hidden danger of quality, the most serious is that element can't be welded on PCB above or circuit disconnects, and product rejection can't be used.
The utility model content
The purpose of this utility model is the defect existed for above-mentioned prior art, and a kind of PCB pad is provided.
The technical solution adopted in the utility model is a kind of PCB pad of design, comprises the fairlead that is arranged on pcb board and is arranged on the Copper Foil around this fairlead, wherein, the periphery that is positioned at described Copper Foil on the pcb board formation copper paving area that stretches out.
In one embodiment, described copper paving area is provided with at least one via hole, and the copper paving area of described pcb board both sides is connected by described via hole.
Compared with prior art, in the utility model by setting up copper paving area, increase bonding pad area, the contact area of Copper Foil and pcb board strengthens, strengthened the adhesive force of Copper Foil, strengthened quasi-viscous effect, the Copper Foil on pad is not easy to occur the phenomenon that warps or come off, and the larger radiating effect of area is better, the temperature of the pad that is conducive to leave fast.
The accompanying drawing explanation
The structural representation that Fig. 1 is a kind of PCB pad of prior art;
The cutaway view that Fig. 2 is A-A face in Fig. 1;
The structural representation that Fig. 3 is the utility model one embodiment;
The cutaway view that Fig. 4 is B-B face in Fig. 3.
Embodiment
Below in conjunction with drawings and Examples, utility model is described in detail.
As shown in Figure 3, the PCB pad the utility model proposes comprises the fairlead 2 be arranged on pcb board 1 and is arranged on this fairlead 2 Copper Foil 3 on every side that wherein, the periphery that is positioned at described Copper Foil 3 on pcb board 1 stretches out and forms copper paving area 4.
From Fig. 3 and Fig. 4, can find out, the two sides of pcb board 1 is provided with pad, pad comprises the fairlead 2 be arranged on pcb board 1 and is arranged on this fairlead 2 circle Copper Foil 3 on every side, Copper Foil 3 is annular, on pcb board 1, Copper Foil 3 peripheries of this pad outwards expand and form a circle for increasing the copper paving area 4 of paving copper sheet, and this copper paving area 4 is connected with Copper Foil 3, copper paving area 4 areas of setting up can be greater than the area of Copper Foil 3.Adopt this mode can increase the contact area of copper and pcb board 1 on pad, sticky area is larger, and quasi-viscous effect is better.
In one embodiment, from Fig. 3 and Fig. 4, can find out, copper paving area 4 is provided with four via holes 5, the copper paving area 4 on pcb board 1 two sides is connected by this via hole 5, and mutually is attached together.By increase via hole 5 on pad, can make the copper paving area 4 on two sides interconnect through after this via hole 5, increase absorption affinity; And under hot environment, via hole 5 is conducive to breathe freely, and is improved effect to expanding with heat and contract with cold.
Using method: during installation, component pin 6, by the fairlead 2 on PCB, will melt tin by flatiron, with scolding tin, is weldingly fixed on the Copper Foil 3 of setting up on pcb board 1, and printed conductor couples together pad, realizes the electrical connection of element in circuit; During dismounting, open flatiron and be adjusted to higher temperature, in order to the scolding tin on component pin 6 is melted or removes, after scolding tin melts or removes, take advantage of when element becomes flexible and pull it, because the area change of copper sheet, strengthen the viscosity of Copper Foil 3 on pcb board 1, but also increase, four via holes 5 are arranged, make the copper paving area 4 of two pcb board 1 both sides be connected, increased the adhesive force of copper paving area 4 on pcb board 1, when pulling out pin, can not make Copper Foil 3, copper paving area 4 on pad the phenomenon that warps or come off occur.
Of the present utility model by setting up copper paving area, increase bonding pad area, the contact area of Copper Foil and pcb board strengthens, strengthened the adhesive force of Copper Foil, strengthened quasi-viscous effect, Copper Foil on pad is not easy the phenomenon that warps or come off to occur, and the larger radiating effect of area is better, the temperature of the pad that is conducive to leave fast.